Conventionally, reduction in thickness (thinning) of a silicon carbide wafer has been attempted in order to reduce a thickness of a silicon carbide element. When reducing a thickness of a silicon carbide wafer, for example, a grinding technique is used. On the other hand, when reducing a thickness of a silicon carbide wafer, warpage may be generated. As a technique for eliminating such warpage, for example, the following technique is proposed in WO2012/049792 (paragraph [0038]). (1) After thinning is performed, a Ni film is formed on a back surface, and then laser annealing is performed to the Ni film, thereby forming a silicide layer. (2) By thinning a substrate (wafer) as described above, large warpage is generated. However, an amount of the warpage of the substrate (wafer) is adjusted by removing (surface-treating) at least a part of an affected layer formed on a ground surface after the thinning.